Positioning means for material cutter

ABSTRACT

A material cutting device having a backgauge which may be manually positioned by means of a hand wheel accessible to the operator also includes a position indicating tape upon which visible indicia representing the backgauge position are printed or engraved. The visible indicia may be referred against an index mark located adjacent a circular scale mounted to rotate with the hand wheel. The close proximity of the circular scale, the index mark, and the visible indicia on the control tape facilitates the positioning of the backgauge by the operator.

United States Patent [151 3,66 1 ,277

Young May 9, 1972 s41 POSITIONING MEANS FOR MATERIAL FOREIGN PATENTS ORAPPLICATIONS CUTTER [72] Inventor: Dorse James Young, Centerville, Ohio[73] Assignee: Harris-lnteI-type Corporation, Cleveland,

Ohio 1 [22] Filed: Jan. 8, 1970 [21] Appl. No.: 1,506

[52] U.S.Cl ..2l4/I.6,116/115.5

[51 Int. Cl ..B23q 7/00 [58] Field ofSearch ..214/1.5-1.7;

[56] References Cited UNITED STATES PATENTS 2,071,402 2/1937 Hazelton..83/522 X 2,213,068 8/1940 Eickman 2,673,611 3/1954 Seybold 3,527,1289/1970 Thumin ..214/1.6X

521,684 2/1956 Canada ..116/ll5.5

714,183 10/1941 Germany ..83/522 932,344 7/1963 Great Britain ..83/522618,634 3/1961 Italy ..83/522 Primary Examiner-Gerald M. ForienzaAssistant E.vaminer-Frank E. Werner Attorney-Marechal, Biebel, French &Bugg ABSTRACT 3 Claims, 5 Drawing Figures PATENTEDMAY 9 I972 3.661.277

sum 1 0F 2 FIG 1 RELATED APPLICATION Reference is hereby made toapplication Ser. No. l,407, filed Jan. 8, I970 assigned to the sameassignee as the present invention.

BACKGROUND OF THE INVENTION In material cutting devices, such as shownin US. Pat. No. 3,176,556, the position of a backgauge which moves apile of material beneath a clamp and knife for cutting is indicated by acontinuous, flexible metal indicator tape connected to move with thebackgauge. Typically, the indicator tape is carried above a tablesupporting the material while the hand wheel by which the operatorpositions the backgauge manually is connected directly to a lead screwrotatably supported beneath the table. The indicator tape is usuallyfirst referred to by the operator to position the backgauge to a firstorder of accuracy. The operator must then shift his eyes from theindicator tape located above the table to a circular scale, usuallylocated below the table and mounted on the hand wheel, for the finalpositioning of the backgauge to a second order of accuracy.

Since the machine operator must refer to widely spaced locations inorder to position the backgauge manually, and thus the material on thetable, the operator must be careful and take time so as not to positionthe backgauge inaccurately.

SUMMARY OF THE INVENTION This invention relates to a novel arrangementof an indicator tape and circular scale for positioning a backgauge of amaterial cutter whereby the machine operator may refer to only onelocation to ascertain quickly the position of the backgauge.

A hand wheel is connected to a lead screw supported for rotation beneaththe table for positioning the backgauge. In the preferred embodiment,the flexible indicator tape is part of a control mechanism located atthe forward part and underneath the table and moved in response to therotation of the lead screw. The indicator tape is a magnetic tape uponwhich control marks may be recorded and thereafter used to position thebackgauge automatically. The indicator tape is provided with visibleindicia which is divided into units of length, and fractions thereof,and may be observed through an opening in the housing of the controlmechanism. By comparing the indicator tape to an index mark on thehousing, the backgauge position may be ascertained to a first order ofaccuracy.

A circular scale mounted to rotate adjacent the opening in the controlmechanism housing also carries on it visible indicia which may bereferenced to the index mark on the housing to indicate the position ofthe backgauge to a second order of accuracy. The circular scale iscorrelated to the movement of the backgauge so that one revolution ofthe scale is equivalent to one unit of length as defined on theindicator tape.

Due to the close proximity of the visible indicia on both the circularscale and the tape, the operator need only refer to a single location toascertain accurately the position of the backgauge.

Accordingly, it is an object of this invention to provide an improvedmaterial cutting device in which an indicator tape having visibleindicia placed thereon is mounted adjacent a circular scale whichrotates with a lead screw moving a backgauge, the visible indicia onboth the tape and the scale being observable by a machine operator atessentially one location; and to provide an improved material cuttingapparatus wherein a continuous magnetic control record which may be usedto position a backgauge automatically also carries thereon visibleindicia which, as observed by the machine operator, is located adjacenta circular scale connected to rotate with the lead screw driving abackgauge.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of amaterial cutting device which includes the position indicating apparatusof this invention;

FIG. 2 is a front elevational view showing a flexible indicator tape inconnection with the lead screw which moves the backgauge;

FIG. 3 is a plan view showing in part the relationship between theflexible indicator tape and the circular scale connected to rotate withthe lead screw;

FIG. 4 is a side view, particularly in cross section, showing therelationship between the flexible indicator tape and the circular scale;and

FIG. 5 is an enlarged view taken on the view line 5-5 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,the position indicating apparatus of this invention is preferably usedon a material cutting apparatus, shown generally in FIG. 1, whichincludes a table 10 upon which a stack of material 11, such as paper,may be placed to be cut by a knife 12. A clamp 13 holds the materialduring cutting while backgauge 15 positions the material beneath theknife. The backgauge is moved by a lead screw 17 rotatably supportedbeneath the table. A slot 18 is formed in the table 10 and receives anextension of the backgauge 15 which cooperates with the lead screw 17 tomove the backgauge. A hand wheel 20 is attached to one end of the leadscrew and permits the machine operator to position the backgaugemanually. The backgauge is also supplied with power from a drive means21 for positioning the backgauge automatically under the direction ofposition control means, shown generally at 25.

The position control means 25 is contained in a housing 27 and includesa flexible continuous tape 30 which is reeved over a sprocket wheel 31and a roller 32. The sprocket wheel 28 has formed thereon a plurality ofpins 33 which engage sprocket holes 34 in the tape 30 to provideaccurate and positive control over the movement and position of thetape.

The sprocket wheel 31 is connected to rotate under the control of thelead screw 17 through a chain 35 drivingly connected to the lead screwby a sprocket wheel 36 and to the sprocket wheel 31 through gears 37 and38 and sprocket 39.

The sprocket wheel 31 is carried in a carriage 41 which is slidablymounted within the housing 27. A spring 42 connected between thecarriage 41 and the housing 27 urges the carriage 41 to the left, asviewed in FIG. 3, and therefore places the chain 35 in tension.

The roller 32, which supports the right end of the tape 30, is alsomounted in a carriage 43, and this carriage is biased to the right, asviewed in FIG. 3, by a spring 44. The spring constant of spring 44 isless than that of spring 42 so as not to lessen substantially thetension on the chain 35 while at the same time permitting the tape 30 tobe supported between the sprocket wheel 31 and the roller 32 withoutslack.

In the preferred embodiment, the gear ratios between the sprockets 36and 39, and the gears 37 and 38 are so selected that the tape 30 movesthrough the same linear distance as the backgauge 15. The tape 30carries on it visible indicia to which the operator may refer toascertain the position of the backgauge 15. The visible indicia is inunits of length, typically inches, and fractions thereof, i.e., A-inchdivisions, thus allowing the operator to ascertain the position of thebackgauge to a first order of accuracy.

The visible indicia may be viewed through an opening 50 formed in thehousing 27. This opening is preferably provided with a window 51 whichincludes an index mark 52 against which the visible indicia may bereferenced.

The hand wheel 20, as shown in FIGS. 4 and 5, has mounted thereto acircular scale 55 which is also provided with visible indicia,preferably by engraving. The circular scale 55 rotates adjacent thewindow 51, and the marks thereon may be observed by reference to theindex mark 52.

The pitch of the lead screw 17 may be selected so that for one completerevolution of the lead screw, the backgauge will move one unit of length(ie 1 inch). Thus the circular scale 55 is divided into small fractionsof that unit of length and provides means for ascertaining the positionof the backgauge within one of those units of length to a second orderof accuracy.

Both the visible indicia on the circular scale 55 and on the tape 30 areobservable by reference to a single location 60 to ascertain theposition of the backgauge 15, the indicia on the tape 30 indicating theposition of the backgauge to a first order of accuracy and the indiciaon the circular scale indicating the position to a second order ofaccuracy.

In the preferred embodiment, the tape 30 is a magnetic tape upon whichmagnetic control marks may be placed which may be sensed by magneticrecording and/or playback heads 65 which form part of the automaticcontrol mechanism. The backgauge 15 is usually positioned manually bythe operator who rotates the hand wheel 20 and refers to the visibleindicia on the tape 30 and the circular scale 55 in order to positionthe backgauge accurately. Electronic circuitry is provided to recordthat position on the magnetic tape 30 so that in subsequent operationsof the material cutting device, the backgauge will be made to stop againin that position.

The tape 30, while designated to be continuous, is actually a length ofmagnetic recording tape which has been spliced at one location. Thelength of the tape used in the preferred embodiment is such that thesplice will never come into view through the window 51 and will nottraverse the magnetic playback and/or recording heads 65. This is doneby making the tape longer than the distance through which the backgauge15 travels by an amount at least equal to the distance between theposition of the recording heads 65 and the window 51.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. Apparatus for indicating the position of a movable member byreference to two position indicating means observable at a singlelocation, said apparatus comprising means for moving said member;

first means for indicating the position of said member to a first orderof accuracy, said first means including a flexible magnetic tapeconnected to move in response to the movement of said member and havingvisible indicia placed thereon, said tape having control marks recordedthereon;

sensing means responsive to said control marks for automaticallypositioning said member in preselected locations; and

second means mechanically connected to said member for indicating theposition of said member to a second order of accuracy, said second meansincluding a circular scale having visible indicia thereon, said scalemounted to rotate adjacent said tape in response to the movement of saidmember;

the indicia on said first and second means being observable at a singlelocation to ascertain the position of said member to both said first andsecond orders of accuracy.

2. The apparatus of claim 1 further including an index mark to whichboth the visible indicia on said tape and said scale may be referenced.

3. The apparatus of claim 1 wherein said flexible magnetic tape moves inone to one relation with the movement of said member, said visibleindicia on said tape being divided into units of length, said scalebeing so related to the movement of said member that one revolution ofsaid scale is equivalent to one ofsaid units oflength.

1. Apparatus for indicating the position of a movable member byreference to two position indicating means observable at a singlelocation, said apparatus comprising means for moving said member; firstmeans for indicating the position of said member to a first order ofaccuracy, said first means including a flexible magnetic tape connectedto move in response to the movement of said member and having visibleindicia placed thereon, said tape having control marks recorded thereon;sensing means responsive to said control marks for automaticallypositioning said member in preselected locations; and second Meansmechanically connected to said member for indicating the position ofsaid member to a second order of accuracy, said second means including acircular scale having visible indicia thereon, said scale mounted torotate adjacent said tape in response to the movement of said member;the indicia on said first and second means being observable at a singlelocation to ascertain the position of said member to both said first andsecond orders of accuracy.
 2. The apparatus of claim 1 further includingan index mark to which both the visible indicia on said tape and saidscale may be referenced.
 3. The apparatus of claim 1 wherein saidflexible magnetic tape moves in one to one relation with the movement ofsaid member, said visible indicia on said tape being divided into unitsof length, said scale being so related to the movement of said memberthat one revolution of said scale is equivalent to one of said units oflength.